Glad to hear they took care of it for you. I've always liked Bushmaster, even though I don't own one. I'm not sure about the 7.62, but I do know that M4 feed ramps make a huge difference in the .223/5.56 AR's. I do know that many of the M4 style Bushmasters (not sure about the longer barrel rifles) don't come with the proper feedramps, but some do. Sounds like that was the problem. I run C Products and Colt mags and both feed reliably, but again it's a 5.56.